Organization and Summary of Significant Accounting Policies - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reclassification [Line Items]
Loans and leases held for investment	$ (2,627,286)	$ (5,145,082)	$ (2,627,286)
Provision for loan and lease credit losses		(40,658)	(15,212)	$ (5,558)
Loan servicing asset revaluation	4,135	$ 9,958	16,581	21,224
CARES ACT of 2020 government guarantee percentage		100.00%
Paycheck Protection Program Loans
Reclassification [Line Items]
CARES ACT of 2020 government guarantee percentage		100.00%
Restatement Adjustment
Reclassification [Line Items]
Loans and leases held for investment	$ 20,000		20,000	18,000
Provision for loan and lease credit losses			(4,400)	(7,500)
Loan servicing asset revaluation			$ 11,800	$ 2,500